The present invention relates to an optical device package of the type that houses various optical devices in a case and leads them off the case through optical fibers optically coupled therewith for external connection and, more particularly, to an optical device package that permits optical coupling of optical devices and fibers without involving their relative positioning to place their optical axes in accurate alignment.
FIG. 1 depicts the construction of a conventional optical device package. Reference numeral 10 denotes a case; 20 denotes optical devices; 30 denotes a substrate with the optical devices 20 mounted thereon, 40a, 40b denotes lens array panels mounted in opposite sidewalls of the case 10 and each having plural lens arrays 41 arranged in plural columns, 43 denotes spacers; 50 denotes single-mode optical fibers arranged in a tape-like form in this example, and 60a, 60b denotes optical connector ferrules attached to end portions of the optical fibers 50.
The substrate 30 is usually a semiconductor substrate, on which the optical devices are mounted. The optical devices that can be housed in the case 10 are, for example, optical switches, light emitting elements, light receiving elements, and so forth.
Turning now to FIG. 2, a brief description will be given of an optical path configuration in the case where optical switches 20 are housed in the case 10. FIG. 2 is a diagrammatic showing of the optical switch structure. The substrate 30 has formed in its top surface a depression (not shown) of the same depth over the entire area thereof, in which hinge-supported vertically moving plates 21 are placed as shown. Mounted on each vertically moving plate 21 are mirrors M1, M2, M3 and M4, which are disposed with their reflecting surfaces tilted at 45 degrees to the optical axes of the lenses 41a held in the lens array panel 40a, 40a. With voltage application to electrodes formed on the vertically moving plate 21 and the substrate 30, the plate 21 moves down vertically to its surface due to electrostatic attractive force, bringing down the mirrors M1, M2, M3 and M4 and held at the down position.
In this example, the optical switch 20 switches between the state in which the plate 21 is in the up position where the mirrors M1 and M2 reflect incident light from an optical fiber 50A for transfer to an optical fiber 50B and the state in which the plate 21 is in the down position where the incident light from the optical fiber 50A passes over the mirror M1, then impinges on and is focused by the corresponding one of the lenses 41b (not shown) of the lens array panel 40b on the side opposite the optical fiber 50A and the focused light is launched into an optical fiber 50C. FIG. 2 shows the case where four such optical switches are housed in the case 10. For details of this optical switch, refer to Japanese Patent Application Laid-Open Gazette 2000-121967.
The optical fiber 50 is a well-known single-mode optical fiber. The lenses 41 of the lens array panel 40a, 40b are optical fiber segments obtained by cutting, for example, a graded index optical fiber short and inserted in lens receiving holes made through a lens holding plate 42.
In the lens array panel 40 there are mounted plural lens arrays arranged in columns. The optical connector ferrule 60a, 60b is held at such a position that it is aligned with that of the lens arrays which is in alignment with the optical axes of the optical devices 20. This brings the optical axes of the optical fibers 50 into alignment with the optical axes of the optical devices 20 housed in the case. Thereafter, the optical connector ferrule 60a, 60b is bonded to the case 10.
The conventional optical device package has the construction in which the optical axes of the optical fibers 50 supported to the optical connector ferrule 60a, 60b are optically coupled to the optical devices 20 through the lens array 40a, 40b mounted in the sidewalls 10Sa, 10Sb of the case 10. Hence, when the optical connector ferrule 60a, 60b is attached to the case 10, much time is required to make adjustments for bringing the optical axes of each optical fiber 50 held by the optical connector ferrule 60a, 60b into alignment with the optical axis of the corresponding lens 41 of the lens array 40a, 40b. This seriously impairs the productivity of the optical device package.
Moreover, it is also troublesome and time-consuming to make adjustments for placing the optical axes of the lenses 41 of the lens array 40a, 40b and the optical devices 20 in alignment with each other.
It is therefore an object of the present invention to provide an optical device package that is free from the necessity for the positioning and hence is easy to fabricate.
The optical device package according to an aspect of the present invention comprises:
a substrate having mounted on its one side optical devices and having formed in said one side positioning parts for defining the positions of optical axes of the optical devices;
a case with the substrate housed therein;
an optical connector ferrule mounted in the case;
flexible optical waveguides held at one end in optical fiber receiving holes made in the optical connector ferrule and having the other ends extended into the case and positioned in the positioning parts to provide optical coupling between the flexible optical waveguides and the optical devices; and
a ferrule coupler provided on the end face of the optical connector ferrule externally of the case, for optically coupling optical fibers held in another optical connector ferrule to the flexible optical waveguides.
According to another aspect of the invention, the substrate is a semiconductor substrate and the positioning parts are V grooves cut in the semiconductor substrate in parallel to the optical axes of the optical devices.
According to another aspect of the invention, the flexible optical waveguides are each formed by a graded index optical fiber that focuses light emitted therefrom.
According to another aspect of the invention, the flexible optical waveguides are each formed by a TEC optical fiber that focuses light emitted therefrom.
According to another aspect of the invention, the ferrule coupler comprises pins projecting from one of the optical connector ferrules and pin receiving holes made in the other optical connector ferrule.
According to still another aspect of the invention, misalignments between the optical axes of the optical devices and the axes of the optical fiber receiving holes of the optical connector ferrule and their misorientations are accommodated by deforming the flexible optical waveguides.
With the optical device package structure of the present invention, the optical devices and the optical connector ferrule mounted in either of opposite sidewalls of the case are interconnected by flexible optical waveguides, and end portions of the flexible optical waveguides are positioned by the positioning parts formed on the part of the optical devices to provide optical coupling between the flexible optical waveguides and the optical devices. Hence, the positioning can be accomplished simply by placing and fixing the end portions of the flexible optical waveguides in the positioning partsxe2x80x94this permits easy fabrication of optical device packages.
Further, since each optical connector ferrule mounted in one sidewall of the case is provided with an optical connector ferrule coupler, another optical connector ferrule having connected thereto is automatically positioned relative to and connected to the optical connector ferrule mounted in the sidewall of the case. Accordingly, the present invention allows assembling of the optical device package without involving the positioning, and hence it permits easy assembling and fabrication of optical device packages with increased productivity.